Improvements in nonlinear elasticity and strength by grain refinement in a titanium alloy with high oxygen content

Abstract

This paper reports an ultrafine-grained Ti-24Nb-4Zr-8Sn-0.4O (wt.%) alloy produced by warm rolling at 673 K, showing notable nonlinear elastic deformation with a recoverable strain of similar to 3 A as well as a tensile strength of 1200 MPa, Young's modulus of 56 GPa and elongation of 8%. A duplex microstructure with nanosized alpha precipitates in ultrafine-grained beta matrix was obtained by a subsequent three-step heat treatment to achieve a tensile strength of 1700 M Pa, a fatigue strength of 1050 M Pa and an elongation of 5%. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.